Generally, where heavy hydrocarbons such as asphalt, coal tar, heavy oils and crude petroleum are thermally cracked in a reactor, coke is formed and the coke deposits on the inner wall of the reactor. Accordingly, in order to operate the reactor efficiently it is necessary to remove the coke from the inner wall of the reactor.
In the prior art method for removing coke from the inner wall of the reactor, the operation of the reactor is suspended and after cooling the reactor, the coke is mechanically removed by a conventional cleaning method employing, for example, a waterjet. Such a method, however, suffers from the disadvantage that the reactor requires temporary shutdowns.